[Experimental study on the effect of forced running on occurrence of osteoarthritis in the knee of C 57 BL mice].

We investigated the effects of running load on the development of osteoarthritis (OA) in C 57 black male mice (Silberberg), a strain which spontaneously develops OA of the knee joint, and in Std:ddy male mice, a strain which does not develop OA. Six-week-old mice of both strains were randomly assigned to a non-forced running (control) group or forced running groups, which ran on treadmill 1 or 2 hours per day of 5 day/week program. Six, 18, and 30 weeks after the running period, the mice were sacrificed and the knee joints examined histologically and bone morphometrically. In the control C 57 black mice, OA occurred at 6 months of age, while in the forced running C 57 black mice, OA occurred at 3 months of age (6 weeks after the end forced running). In 6 and 9 months old C 57 black mice the incidence of OA in the forced running group was higher than that in corresponding control group. These data suggest that forced running load accelerates the process of OA in the knee joint in young mice of a strain which spontaneously develops OA.